Filling device



y 1960 F. E. O'NEILL FILLING DEVICE Filed July 26, 1956 I hf M H U Z M. E R Y 3 a 3 3 j A m, 7

FIG.3

FIG.2

FIG. l

IN ENTOR. FRANK E. O'NEILL BY M ,/ZM

HIS ATTORNEY 2,944,606 FILLING DEVICE Frank E. ONeill, Glendale, Calif., assignor to Johnston Testers, Incorporated, Houston, Tex., a corporation of Texas 1 This invention relates to apparatus for filling well pipe and, more particularly, to apparatus for filling well pipe with a so-called water. cushion or fluid column above formation testing tools carried by the pipe.

In testing the fluid production of earth formations at a considerable depth in -a well, the pipe throughwhich into a well and recovered fluids are passed to the surface must-Withstand I valve shown in Fig. -1 for filling the pipe string; and

the high hydrostatic pressure of weighting fluids commonly filling the well. To prevent collapse of the pipe by this pressure while making relatively deep tests, at least the lower portion of the pipe is often filled with a column of weighting fluid, such as water or drilling mud. In testing a formation at a depth of 8,000 feet, for example, a fluid column 2,000 'feet in height may be employed. In either shallow or deep tests, on the other hand, a fluid column may be employed to retard or cushion the initial flow of fluid into the pipe and is thus aptly termed a water cushion. Because oflth'eizhydrostatic head of thewater cushion, the packed oif .zone is not subjected to a sharp reduction in pressure whenput on test ,.and cave-ins, blocking of perforations, and the like are thereby avoided.

Frequently, a.,water cushion is obtained .sim ply by connectinga source of water to the open. end of the pipe at the well head. Filling the pip'ein this mannerrequires an interruption in thesequence of making up joints 2- to submerge a valve carried above a formation tes-ter by the pipe. The well fluid is admitted through sideports in the valve to provide a fluid column or water cushion of desired height within the pipe. A longitudinal passage through the valve is then blocked by plug means lowered through the pipe and including a core of fusible material. Pump pressure is applied through the pipe downwardly upon the plug means to close the valve. Thereupon, the pipe is lowered such further distance as is desired to bring the formation tester opposite the zone to be tested. The increase of ambient temperature with depth causes the fusible material of the plug means to soften and no longer to obstruct the passage through the valve.

The invention and others of its objects and advantages will be perceived from the following detailed descrip- Fig. 1 is a schematic diagram of apparatus extending tion;

Fig.2 is an enlarged view, partly in section, of the Fig. 3 is a view similar to Fig. 2 but showing the valve in its closed, unobstructed condition.

in Fig. 1 is shown a well 10, either cased or uncased, extending through ear-th formations 11 including a zone which isto be tested for fluid production. A pipe string 12extends into the well and is supported at the well head, 'as by means of conventional slips,13. Elevating apparatus (not shown) may also be located at the well head for making up sections or joints ofpipe to form the pipe string 12, as it, is loweredinto the well. To exemplify the practice of the invention, there is shown a formation tester 14. connected atjthe lower end of the pipe string and including at leasta main valve which isfclosed jas the pipe stringis lowered into the well and excludes Qwell. fluid 15' from entering the pipe string of pipe into aistring for lowering intothe well, with .a

consequent loss of' time. .Furthermore,- a considerable amount of air is entrained with the water as itdrops through the pipe. Unless additional time is talgen to allow escape of this air fromthe water cushion,.i air pockets in the water cushion may lower .its; hydros'tatiehead below safeflimits.

In accordance with the teachings of copending application Serial No. 548,061, filed November 21, 1955 by T. H. Sackett and P. H, Glass -for -Fill-Up Valveifor Well Strings, a valve niaybe incorporated 'in the pipe string to admit well fluid to the pipe as itlis lowered into a well. Such a valve includes a lbody having side ports for admitting Wellfluids and a sleeve slida'ble within the bodyand arranged ,to beplu'ggedby a go devil. The sleeve is forged downwardly y'puin pressure when plugged, therebyto closelthe "side ports were suflicient air-free water' cushion has beenreceived. 1 i

'An object of this invention is to provide new and 'improved apparatus for filling pipe with a column of well fluid v t Another object of this invention is to provide new and improved apparatus for filling pipe'with a column of well fluids of desired height as the pipe is lowered into the Well; without leaving the pipe obstructed; s

A further object of this invention is to-provide new and improved apparatus of-the foregoingJcharacter which;

are convenient andsafe in. use and afford-a saving in the.

time required to. fill pipe with a. fluid column ofdesired height.

by lowering pipe into a well containing weighting fluid through the tester. A varietyof formation testers may be employed. For illustrative purposes, the formation tester 14 is shown to comprise a main or retaining valve assembly 16, a packer '17 connected below the valve assembly 1'6, perforated pipe 18 connected below the packer to admit the"fluid sample, a pressure recorder housing 19 therebelow, and anchor-pipe 20 at the bottom of the pipe string. The valve assembly 16 may suitably be of the type'shown and described at page 2721 of; the Composite Catalog of Oil Field and Pipe Line Equipment, 21st (195556) edition, published by the Gulf Publishing Company, and combining the functions of a by-pass or equalizing valve, a main or retaining valve, a shut-in pressure valve, and a reverse circulating valve, as well as a downwardly opening check valve. 'If desired, of course, one or more of these functions could be performed by separate valves appropriately connected in the pipe string. 7 The pipe string itself may be of the type comrnonlyreferred to as a drill string, a tubing string orthe like, and generally affords a'fluid-tight longitudinal'passage for the flow of recovered fluidsto the surface.

Connectedv in the, pipe string 12 above the formation tester is a valve 22 embodying principlesof the valve disclosed in the above-mentioned application Serial No. 548,061. The valveincludes a tubular body 23 connected by threaded box and pin ends 24, 25 in the pipe string and having a longitudinal passage 26 through it submergedgi'n the .well' fluid 1'5 with. which the well 11 is weighted.

mud; salt water; or the like, to flow' into. the; pipe string and form a fluid column or water cushion,- the valve Patented July112, 1960 arranged in accordance with the inven- 22 has 'side ports 32 extending radially through the body 23 to place the exterior and interior of the valve in communication. Well fluid entering the longitudinal passage 26 of valve 22 from the side ports may flow downwardly a short distance into passage 33 of the formation tester 14 until it is filled and upwardly into passage 27 of the pipe string until the fluid level within the pipe string equals the fluid level 34 in the annulus exterior to the pipe string.

To close the side ports 32, a sleeve 35 is slidably received in bore 36 of the valve 22 for movement downwardly across the inner ends of the side ports (as seen in Fig. 3). O-rings 37 spaced above and below the side ports 32 are carried by the body 23 and seal with the sleeve 35 in its closed, lower position to prevent leakage. To prevent premature closing of the sleeve valve, a shear pin 38 is retained in the body 23 of the valve and extends inwardly for reception in a recess 39 in the per- 7 iphery of the valve sleeve 35. This shear pin may be positioned to retain the sleeve 35 in its open position before the valve is connected in the pipe string and has a predetermined shear strength.

To close the sleeve valve by a remote operation at the surface, there is provided a plug 40 of the .go-devil type which may be dropped into the upper open end of the pipe string to fall through the Water cushion or fluid column therein into engagement with the sleeve 35. In accordance with the present invention, this plug 40 is arranged to temporarily obstruct the passage 26 so that fluid pressure may be applied at the Well head to force sleeve 35 into its lower, closed position. However, the plug 40 is arranged not to obstruct either downward or upward flow of fluid through the pipe string when the pipe string has been lowered a further distance into the well.

To this end, the plug 40 of this invention comprises an annular sealing section 41 and a plugging section 42. These sections 41, 42 are joined together, as by thread connection 43. The sealing section 41 has a downwardly and outwardly facing surface 45 which is tapered complementary to an outwardly and upwardly flared surface 46 encircling passage 47 through the sleeve 35. To effect a fluid tight seal between the sealing section and the flared surface 46, the tapered surface 45 of the sealing section may be relieved to receive an annular sealing element 48 composed of a resilient material, such as rubber or the like. The sealing element 48 may be bonded, if desired, to the sealing section and has an outer surface conforming with the upwardly flared surface 46 of the sleeve 35.

The plugging section 42 of the go-devil 40 has a rigid annular portion 49 in which is molded or otherwise received a core 59 of fusible material. The annular portion 49 serves to secure the core '50 to the sealing section 41 through the thread connection 43 and has a plurality of annular retaining grooves 52 in its inner surface which receive the core material and strength the interengagement of the core 50 and annular portion 49. The annular portion 49 may also have an upwardly and outwardly flared interior surface 53 at its upper end, similar to flared surface 46, and serves both to retain the core 50 and to provide an emergency seat for a further go-devil.

The go-devil type plug 40 has an outside diameter appreciably less than the inside diameter of the pipe string to provide an annulus through which the water cushion may be displaced as the plug descends into engagement with the valve sleeve 35. The composition of the core material is such that during this descent, the ambient temperatures encountered are insuflicient to' soften or melt the core. When, however, the plug has served its purpose in closing. of the valve 22 and the pipe string is lowered further in the well, it is desirable that the plug 50 should soften sufliciently that fluids may be circulated downwardly through the pipe string and through downwardly opening check valves in the formation tester. Such downward circulation of fluid is resorted to in an emergency to allow introduction of weighting fluids, such as heavy drilling muds, to overbalance formation pressures. In other instances, downward circulation may be employed to assist in freeing the pipe string, should it tend to become stuck while descending into the well.

Suitably, the core 50 of the go-devil is composed of a fusible material such as wax or the like which has sufficient hard strength to resist pumping pressures required to actuate the valve 22. The material is further of a type which softens or melts at ambient temperatures prevailing at the lower depths of wells. In its melted state, the material is of a kind which does not adversely affect further operations in the well or contaminate the-recovered fluids. It will be appreciated that the plug 50 will fail at a lower temperature where a higher pump pressure is employed and, conversely, will fail at a higher temperature when a lower pump pressure is employed. Failure of the plug is also dependent upon its dimensions and the manner in which it is interengaged with the annular portion 49 of the plug. With these considerations in mind, selection of an appropriate material, such as a suitable wax, may readily be made.

For example, a wax having a melting point between 195 and 200 F. has been found suitable in field practice. Such a wax may be obtained from the Bareco Wax Company, Tulsa, Oklahoma, and has the trade designation Crown-200. Crown 1035 may also be used. A variety of other petroleum waxes may alternatively be employed, such as Sunwax 1290 made by the Sun Oil Company, Philadelphia, Pennsylvania, having a melting range of 175-185 F., or S/V Cerese made by Socony Mobil Oil Company, Inc., New York, New York'having a melting point of 170 F. In addition, various synthetic waxes may be employed. As examples, Aerawax made by Glyco Products Company, Brooklyn, New York, having a melting point of 95-97 C., Durawax made by Cornelius Products Company, New York, New

, York, and Strobawax, a product of Glyco Products Company having a melting point of 98 C., may each suitably be employed. In general, relatively hard, water insoluble waxes have been found satisfactory and are available with a wide variety of melting or softening temperatures which may suitably be in the range of about to 210 F. r 7

To illustrate suitable means for applying fluid pressure downwardly on the plug 40, there is shown in Fig. 1 a pump 56 having its inlet connected to a fluid reservoir 57 such as a mud pit or water tank, and its outlet connected through a valve 54 to the upper end of the pipe string 12 through a connector 55.

In an exemplary operation according to the invention, the valve 22 and the formation tester 14 are made up with the lower joint of the pipe string by threading and are lowered together into the well. The valve 22 is then retained in its open position by shear pin 38, as is shown in Fig. 2, the plug 40 not yet being inserted in the pipe string. As the side ports 32 of valve 22 are submerged in the well fluid 15 with lowering of the pipe string into the well, well fluid flows along the passages 26, 47 and 27 to maintain the fluid level within the pipe string equal to that exterior to the pipe string. Accordingly, filling of the pipe string progresses automatically and continuously to maintain the pipe string full without attention of the operator or time loss.

When the length of pipe lowered into the Well equals the desired height of the water cushion or fluid column to be retained within the pipe string, steps are taken to close the fill-up valve 22. This may be done, for example, when the pipe string is supported in the slips 13 standgof pipe for assembly with the pipe string. -At this time, the upperend of the. pipe string at-the Well head is opento receive the go-devil or-plug 40. With the core .50 of th'e'plug in its solidified orhard, retained condition,

flaredsurface. 46 of the valve sleeve after a short interval.

Connector 55 is then made up at the upper end'of the pipe string and valve 54 is opened. Since the fluid level within the pipe string is already equal to that of the Well fluid, which is generally maintained at a height only slightly below the slips 13, fluid pressure in the water cushion is quickly, raised to the valve aflorded by the pumping action. Suitable pumping pressures for closing valve 22 may readily be determined by calculations based upon the diameter of the valve sleeve 35 and the shear strength of the shear pin 38 or by a'simple laboratory experiment. In practice, pump pressures in the range of approximately 200-500 p.s.i. are conveniently employed,

although lesser or greater pumping pressures may be used if desired. Hydrostatic pressures acting on the valve and before the elevating apparatus has picked up another sleeve, it may be noted, are substantially balanced, so

that the pump pressure acts to overbalance the hydro static pressure and create a downwardly directed pressure differential across the plug 40.

The force of'fluid pressure acting downwardly on plug 40 is transmitted through the sealing element 48 to the feet. For. example, the valve 22 may be closed at a 2,000

foot depth by 400 p.s.i. pressure with a temperature of,

say, 120 F.1QA 2,000 foot water cushion, is thus obtained.

As the pipev string is lowered to bring the valve. 22 to a depth of 5,000 feet, the plug '50 may be subjected to a temperature of, say:160, F. By a suitable'selection of the core material for the plug, this temperature may be suflicient to soften the plug so' that it no longer may resist a surface pumping pressure of 400 p.s.i.

Since the formation tester is generally not opened until the total desired depth is reached, the plug material normally will be melted before fluids recovered during a formation test are passed upwardly through the pipe string. It is, therefore, unnecessary that the plug 40 be floated out of the pipe string to provide a sufficient passage for the recovered fluids.

While a preferred embodiment has been illustrated and described to exemplify the principles of the invention, the

invention is, of course, subjected to various modifications.

For example, the plug 40 may be made with a variety of other configurations. The sealing section 41 and the annular portion 49 may be unitary, rather than connected by threads 43,- and the grooves 52 interiorly of the annular portion 49 may be eliminated. In lieu of O-rings 37 received by grooves in the valve body 23, seal means may be carried by the valve sleeve for effecting a seal above and below side ports 32. In the practice ofthe in vention, the plug may, if desired, be positioned-above .valve sleeve 35 and causes shearing of the shear pin 38 to I free the, valve sleeve for downward travel. Because the composition of the core 50 of the plug is relatively hard and the core is interfitted with the. annular portion 49 to resist downward movement, the shear pin 38 will .fail

before" the core fails. Side ports 32 are then closed off by the sleeve 35 and seal rings 37.

After removing the connector 55, the remainder of the pipe string is made up by joints'at the surface and lowered in the well to bring the formation tester to a desired depth. Since the thread connections of the pipe string are substantially fluid tight in ordinary practice, no

additional well fluid then enters the pipe string. If desired, closure of the valve 22 may be ascertained by observing the rise in the level of well fluid around the pipe string as additional joints of the pipe string are lowered into the well to displace the well fluid.

As the valve 22 is lowered'in the well, a temperature 7 rise is experienced by the material of the plug core due to increase in the ambient temperature with depth in the well. The softening or melting temperature of the core is conveniently selected at a value occurring intermediate the level at which the valve 22 was closed and the' final depth to which the valve is to be lowered. At least by the time the pipe string is lowered to the desired full depth for operation of the formation tester, the core material has softened to the extent that the core is no longer able to resist fluid pressures which may be developed by pumping action at the surface. Hence, the pump 56 may be connected to the pipe string to force fluids, such as drilling mud, together with the water cushion, downwardly past the valve 22 and through downwardly opening valves in the tester to establish a circulation up the annulus about the pipe string. Such circulation may be required in an emergency to kill the well or to reduce the risk of stuck pipe, for example. Under ordinary conditions, a pump pressure of 700 p.s.i. should overcome the strength of the core 50 after the valve 22 has been lowered an appreciable distance below the depth at which it was closed. Generally, however, the same pumping pressure which suffices to close valve 22 at the depth corresponding to the height of the desired water cushion, suflices subsequently to unblock the valve 22 for downward fiow'of fluid when the valve has been lowered an additional several thousand the valve 22 as shown in Fig. 2, when the valve is made up in the pipe string, since the plug 40 will not, oppose upward flow of well'iluid in'making up the water cushion. Preferably, however, the plug is not introduced into the pipe string until the valve 22 is to be closed. If desired,

' the plugimay be pumped downwardly to effect rapid -fications,its scope is not to be limited tolthe illustrative embodiment but is defined in the appended claims.

I claim:

l. A go-devil for engaging and actuating a sleeve valve i in a pipe string within a well comprising an elongated cylindrical member having a longitudinal passage therethrough, said member having an outer wall portion sized 'to maintain said'mernber in upright position within a pipe string, sealing means for valve sleeve engagement at the lower end of said member and a fusible core disposed in said passagetfilling the same, said core adapted to be softened at selected well temperatures, said core and said member having respective downwardly and upwardly facing shoulders inter-engaging to resist downward movement of said core relative to said member.

2. In apparatus for controlling flow of well fluid between the exterior and interior of a pipe string, the combination comprising a tubular body arranged for connection: in a pipe string and having a side port for the admission of well fluids, a valve member in said body having a longitudinal passage therethrough movable from an initial position permitting flu-id communication through said side port toward another position blocking fluid communication through said side port, releasable means for retaining said valve member in said initial position, and plug means including fusible material extending continousuly between the end portions of said plug means, said plug means adapted to be lowered into said passage and sized for sealing engagement with said valve member to close said passage to fluid flow thereby to permit transmission of an actuating force to said valve member, said material being adapted to be softened by well temperatures to open said plug means for fluid flow between the end portions of said plug means and through the longitudinal passage of said valve member.

3. In apparatus for filling a pipe string with well fluid, the combination comprising a tubular body arranged for connection in a pipe string and having a side port for admitting well fluid, a valve member in said body having a longitudinal passage therethrough movable from'an initial upper position permitting fluid communication through said side port toward a lower position blocking communication through said side port, releasable means for retaining said valve member in said initial position, and plug means including fusible material extending continuously between the end portions of said plug means, said plug means adapted to be lowered into said passage 7 into sealing engagement with said valve member to close the same, said valve member being movable downwardly by fluid pressure when closed by said plug means to close said side port, said material being softened by well temperatures to open said plug means to fluid flow between its end portions and through the longitudinal passage of said valve member.

4. In apparatus for filling a pipe string with well fluid, the combination comprising a tubular valve body arranged for connection in a pipe string and having a side port for admitting well fluid, a valve sleeve in said body normally retained in an initial upper position wherein said side port is open and slidable downwardly to close said side port, and plug means including fusible material extending continuously between the end portions of said plug means, said plug means adapted to be lowered into said valve sleeve in sealing engagement therewith to close the same, said valve sleeve being movable downwardly by fluid pressure acting upon said plug means to close said side port, said material being softened by well temperatures to open said plug means for fluid flow through said valve sleeve after said s ide port has been closed.

5. In apparatus for filling a pipe string with well fluid, the combination comprising a tubular valve body arranged for connection in the pipe string and having a side port for admitting well fluid, a valve sleeveirormally retained in an initial position wherein said side port is open and slidable in said body downwardly to close said side port, and a godevil having a continuous longitudinal passage therethrough, a fusible core filling said passage, said go-devil adapted to be dropped through the pipe string to engage and close said valve sleeve, said vvalve sleeve being movable downwardly by fluid pressure acting upon saidgo-devil to close said side port, said fusible core being composed of a material which is'softened by well temperatures to open the longitudinal passage through said go-devil.

6. Apparatus as defined in claim 5 wherein said core material is a relatively hard wax.

7. Apparatus as defined in claim 6 including means for effecting a'fluid-ti ght seal between said go-devil and said valve sleeve.

8. A go-devil for actuating a sleeve valve in a pipe string within a well, comprising a lower annular section having a tapered sealing surface for engaging a valve sleeve, and an upper core section including an annular member detachably secured to said lower section and a core within said annular member and filling the same, said core and annular member having interfitting raised and recessed portions to resist downward displacement of said core relatively to said annular member, said core being composed of a material fusible in a temperature range extending from about to 250 F. i

9. A go-devil, as defined in claim 8, wherein said core is composed of a relatively hard wax.

References Cited in the file of this patent UNITED STATES PATENTS Baker et al Oct. 13, 1953 

